51 research outputs found

    Automatic Face Reenactment

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    We propose an image-based, facial reenactment system that replaces the face of an actor in an existing target video with the face of a user from a source video, while preserving the original target performance. Our system is fully automatic and does not require a database of source expressions. Instead, it is able to produce convincing reenactment results from a short source video captured with an off-the-shelf camera, such as a webcam, where the user performs arbitrary facial gestures. Our reenactment pipeline is conceived as part image retrieval and part face transfer: The image retrieval is based on temporal clustering of target frames and a novel image matching metric that combines appearance and motion to select candidate frames from the source video, while the face transfer uses a 2D warping strategy that preserves the user's identity. Our system excels in simplicity as it does not rely on a 3D face model, it is robust under head motion and does not require the source and target performance to be similar. We show convincing reenactment results for videos that we recorded ourselves and for low-quality footage taken from the Internet

    Algebraic error analysis of collinear feature points for camera parameter estimation

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    In general, feature points and camera parameters can only be estimated with limited accuracy due to noisy images. In case of collinear feature points, it is possible to benefit from this geometrical regularity by correcting the feature points to lie on the supporting estimated straight line, yielding increased accuracy of the estimated camera parameters. However, regarding Maximum-Likelihood (ML) estimation, this procedure is incomplete and suboptimal. An optimal solution must also determine the error covariance of corrected features. In this paper, a complete theoretical covariance propagation analysis starting from the error of the feature points up to the error of the estimated camera parameters is performed. Additionally, corresponding Fisher Information Matrices are determined and fundamental relationships between the number and distance of collinear points and corresponding error variances are revealed algebraically. To demonstrate the impact of collinearity, experiments are conducted with covariance propagation analyses, showing significant reduction of the error variances of the estimated parameters. © 2010 Elsevier Inc. All rights reserved

    Systematic reviews of complementary therapies - an annotated bibliography. Part 1: Acupuncture

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    Background Complementary therapies are widespread but controversial. We aim to provide a comprehensive collection and a summary of systematic reviews of clinical trials in three major complementary therapies (acupuncture, herbal medicine, homeopathy). This article is dealing with acupuncture. Potentially relevant reviews were searched through the register of the Cochrane Complementary Medicine Field, the Cochrane Library, Medline, and bibliographies of articles and books. To be included articles had to review prospective clinical trials of acupuncture; had to describe review methods explicitly; had to be published; and had to focus on treatment effects. Information on conditions, interventions, methods, results and conclusions was extracted using a pretested form and summarized descriptively. Results From a total of 48 potentially relevant reviews preselected in a screeening process 39 met the inclusion criteria. 22 were on various pain syndromes or rheumatic diseases. Other topics addressed by more than one review were addiction, nausea, asthma and tinnitus. Almost unanimously the reviews state that acupuncture trials include too few patients. Often included trials are heterogeneous regarding patients, interventions and outcome measures, are considered to have insufficient quality and contradictory results. Convincing evidence is available only for postoperative nausea, for which acupuncture appears to be of benefit, and smoking cessation, where acupuncture is no more effective than sham acupuncture. Conclusions A large number of systematic reviews on acupuncture exists. What is most obvious from these reviews is the need for (the funding of) well-designed, larger clinical trials

    Thermal Imaging of Nanostructures by Quantitative Optical Phase Analysis

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    International audienceWe introduce an optical microscopy technique aimed at characterizing the heat generation arising from nanostructures, in a comprehensive and quantitative manner. Namely, the technique permits (i) mapping the temperature distribution around the source of heat, (ii) mapping the heat power density delivered by the source, and (iii) retrieving the absolute absorption cross section of light-absorbing structures. The technique is based on the measure of the thermal-induced refractive index variation of the medium surrounding the source of heat. The measurement is achieved using an association of a regular CCD camera along with a modified Hartmann diffraction grating. Such a simple association makes this technique straightforward to implement on any conventional microscope with its native broadband illumination conditions. We illustrate this technique on gold nanoparticles illuminated at their plasmonic resonance. The spatial resolution of this technique is diffraction limited, and temperature variations weaker than 1 K can be detected

    A Naturally Associated Rhizobacterium of Arabidopsis thaliana Induces a Starvation-Like Transcriptional Response while Promoting Growth

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    Plant growth promotion by rhizobacteria is a known phenomenon but the underlying mechanisms are poorly understood. We searched for plant growth-promoting rhizobacteria that are naturally associated with Arabidopsis thaliana to investigate the molecular mechanisms that are involved in plant growth-promotion. We isolated a Pseudomonas bacterium (Pseudomonas sp. G62) from roots of field-grown Arabidopsis plants that has not been described previously and analyzed its effect on plant growth, gene expression and the level of sugars and amino acids in the host plant. Inoculation with Pseudomonas sp. G62 promoted plant growth under various growth conditions. Microarray analysis revealed rapid changes in transcript levels of genes annotated to energy-, sugar- and cell wall metabolism in plants 6 h after root inoculation with P. sp. G62. The expression of several of these genes remained stable over weeks, but appeared differentially regulated in roots and shoots. The global gene expression profile observed after inoculation with P. sp. G62 showed a striking resemblance with previously described carbohydrate starvation experiments, although plants were not depleted from soluble sugars, and even showed a slight increase of the sucrose level in roots 5 weeks after inoculation. We suggest that the starvation-like transcriptional phenotype - while steady state sucrose levels are not reduced - is induced by a yet unknown signal from the bacterium that simulates sugar starvation. We discuss the potential effects of the sugar starvation signal on plant growth promotion

    Introduction: historical and contemporary perspectives on music, mind and well-being

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    This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book considers the basis of thinking on the topic, while also investigating the different models of the interaction of body, mind and emotions, revealing ideologies that have a significant impact on the questions that scientific and psychological research asks. It also considers what happened to the Greek ideas as they were developed in parallel discourses in the Latin West, the Arabic and the Persian-speaking worlds during the Middle Ages. The book also considers the debate on music’s effects in the late sixteenth- and early seventeenth-century, with particular reference to the composer and lutenist John Dowland. It demonstrates that the evidence that music can distract the listener and performer possibly through inducing a state of “flow” – and in doing so can provide health benefits – is partly historical in character

    Two chloroplast thioredoxin systems differentially modulate photosynthesis in Arabidopsis depending on light intensity and leaf age

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    Various regulatory mechanisms have evolved in plants to optimize photosynthetic activity under fluctuating light. Thioredoxins (TRX) are members of the regulatory network balancing activities of light and carbon fixation reactions in chloroplasts. We have studied the impact of two chloroplast TRX systems, the ferredoxin-dependent TRX reductase (FTR) and the NADPH-dependent TRX reductase C (NTRC) on regulation of photosynthesis by mutants lacking or overexpressing a component of either system. Plants were subjected to image-based phenotyping and chlorophyll fluorescence measurements that allow long-term monitoring of the development and photosynthetic activity of the rosettes, respectively. Our experiments demonstrate that NTRC and FTR systems respond differently to variation of light intensity. NTRC was an indispensable regulator of photosynthesis in young leaves, at light-intensity transitions and under low light intensities limiting photosynthesis, whereas steady-state exposure of plants to growth or higher light intensities diminished the need of NTRC in regulation of photosynthesis. In fluctuating light, overexpression of NTRC increased the quantum yield of Photosystem II (YII) at low light and stimulated the relaxation of non-photochemical quenching (NPQ) after high light exposure, indicating that overexpression of NTRC improves leaf capacity to convert light energy to chemical energy under these conditions. Overexpression of chimeric protein (NTR-TRXf) containing both the thioredoxin reductase and TRXf activity on anntrcmutant background, did not completely recover either growth or steady-state photosynthetic activity, whereas OE-NTR-TRXf plants exposed to fluctuating light regained the wild-type level of Y(II) and NPQ.Peer reviewe

    Flight Demonstration of New Thruster and Green Propellant Technology on the Prisma Satellite

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    The concept of a storable liquid monopropellant blend for space applications based on Ammonium Dinitramide (ADN) was invented in 1997, within a co-operation between the Swedish Space Corporation (SSC) and the Swedish Defense Research Agency (FOI). The objective was to develop a propellant which has higher performance and is safer than hydrazine. The work has been performed under contract from the Swedish National Space Board and ESA. The progress of the development has been presented in several papers since 2000. ECAPS, a subsidiary of the Swedish Space Corporation was established in 2000 with the aim to develop and market the novel “High Performance Green Propellant” (HPGP) technology for space applications. The new technology is based several innovations and patents w.r.t. propellant formulation and thruster design, including a high temperature resistant catalyst and thrust chamber. The first flight demonstration of the HPGP propulsion system will be performed on PRISMA. PRISMA is an international technology demonstration program with Swedish Space Corporation as the Prime Contractor. This paper describes the performance, characteristics, design and verification of the HPGP propulsion system for PRISMA. Compatibility issues related to using a new propellant with COTS components is also discussed. The PRISMA mission includes two satellites in LEO orbit were the focus is on rendezvous and formation flying. One of the satellites will act as a “target” and the main spacecraft performs rendezvous and formation flying maneuvers, were the ECAPS HPGP propulsion system will provide delta-V capability. The PRISMA CDR was held in January, 2007. Integration of the flight propulsion system is about to be finalized. The flight opportunity on PRISMA represents a unique opportunity to demonstrate the HPGP propulsion system in space, and thus take a significant step to towards its use in future space applications. The launch of PRISMA scheduled to 2009
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